Inhalers are commonly used to deliver drugs into the lung of a patient in need thereof. Different types of inhalers have been developed and are available on the market, amongst which dry powder inhalers (DPIs) are becoming attractive in the treatment of various respiratory problems such as asthma, bronchitis or chronic obstructive pulmonary disease (COPD) and for the delivery of non-asthma drugs delivered via inhalation.
In dry powder inhalers, the dose of medicament is present in dry powder form and usually pre-packed in containers such as a capsule. Blister-based dry powder inhalers are also known.
In capsule-based dry powder inhalers, a capsule is placed into a capsule chamber of the inhaler before inhalation and opened, e.g. by piercing the capsule at its ends. Subsequently, the patient inhales through a nosepiece or mouthpiece whereupon an inhalation airflow is generated within the inhaler. The medicament in dry powder form is released from the capsule, entrained into the inhalation airflow and inhaled by the patient.
For dose consistency, it is desirable that as much as possible of the dose of medicament is released from the capsule, inhaled by the patient and delivered to the site of action in the lung.
Medicaments in dry powder form contained in capsules usually consist of a blend of the active ingredient and a bulking agent, e.g. lactose. The powder blend is usually present in form of big agglomerates which are usually a mixture of big and small particles. However, big particles often show a poor release from the capsule and/or a poor lung uptake. Thus, in conventional dry powder inhalers it is desired to break and/or de-agglomerate larger particles into smaller, breathable particles prior or during inhalation in order to allow for an efficient release from the capsule as well as an efficient lung uptake. Particles with a size of not more than 5 μm are believed to be particularly advantageous for an efficient lung uptake.
One approach of breaking down/de-aggregate larger particles inside the capsule during inhalation is to set the capsule into motion thereupon causing impacts between the capsule and the capsule chamber, whereby stronger impacts are believed to lead to a better breakdown of the powder particles and consequently to a more efficient release from the capsule.
Different techniques and capsule chamber geometries have been developed and applied in order to set the capsule into motion during inhalation.
EP 2 739 334 A1 relates to a capsule-based dry powder inhaler wherein the capsule is subjected to a horizontal, propeller-like movement. The inhaler is equipped with means that allow the capsule to serve as an air flow control valve and at the same time, this effect causes repetitive impacts of the capsule against the walls of the chamber in order to improve the outflow of the powder and its breakdown.
EP 1 603 615 B1 relates to an inhaler comprising a capsule chamber having a form and a volume greater than the capsule such that the capsule rotates during inhalation in a propeller-like motion.
U.S. Pat. No. 4,069,819 A relates to a capsule based dry powder inhaler comprising a nebulization chamber for a capsule in which an air passageway is formed in such manner as to set the flowing air in vortical motion such as to cause the capsule, under the action of the flowing air, to make movements of rotation, precession and vibration about and along its longitudinal axis.
However, these approaches often lead to randomly occurring, hardly reproducible and relatively weak impacts between the capsule and the capsule chamber which may cause an unsatisfactory and irreproducible breakdown of the powder and thereby a poor emptying of the capsule.
It is an object of the present invention to provide an inhaler device that overcomes the above problems. In particular, it is an object of the present invention to provide an inhaler device that shows an improved emptying of the capsule during inhalation. It is further an object of the present invention to provide a method for delivering a dose of medicament in dry powder form from a capsule to a patient.